The primary objective is to verify the relation between job strain and clinic blood pressure in a working population from the Milan municipality (1,909 men, 3,786 women) enrolled from 1992 to 1996. Job strain was investigated through the Karasek model. Clinic blood pressure was evaluated using standard procedures from the MONICA project. The association between the two was calculated controlling for age, education, smoking, body mass index, total and high-density lipoprotein (HDL) cholesterol. Significantly, associations were found for systolic blood pressure in men and for both systolic and diastolic blood pressure in women. However, these results do not reflect biological plausibility. The relationship between job strain and blood pressure is an unfinished business: sample characteristics and measurement methods should be carefully considered.